Gas cupola furnace with a special superheat hearth

ABSTRACT

A gas cupola furnace for making metals, said furnace having a hearth comprising various chemical reagents which contact the molten metals for the purpose of changing the chemical composition thereof.

United States Patent [72] Inventors Appl. No. Filed Patented Priority Anatoly Alexeevich Cherney ulitsa Tsiolkovskogo, 41, kv.;

Vladimir Alexandrovich Grachev, ulitsa Uritslogo, 74, kv. 9, Penza; Lev Mikhailovich Marienbakh, ulitsa Bolshaya Cherkizovskaya, Korpus, l, kv. 73, Moscow; Ivan Lukich Kurbatsky, ulitsa Volodarskogo, 70, kv. 4; Efim Davidovich Sosnovsky, ulitsa Sbomaya, 7, kv. 35;

Nikolai Semenovich Pavlenko, ulitsa Dokuchaeva, l, kv. l8, Penza, U.S.S.R. 638,204

May 15, 1967 May 11, 1911 June 27, 1966 GAS CUPOLA FURNACE WITH A SPECIAL SUPERHEAT HEARTH 8 Claims, 1 Drawing Fig.

[52] U.S.Cl 266/11, 266/43, 266/25 [51 lnt.Cl C22b 9/12 [50] Field of Search 266/25, 43, 40, 29; 75/48 [56] References Cited UNITED STATES PATENTS 1,887,453 11/1932 Emmel 75/48X 2,673,083 3/1954 MacPherson et al. 266/43X 2,688,535 9/1954 Madaras 75/48 287,235 10/1883 Chipman 75/48 1 ,329,055 1/1920 .lahova-Merturi 266/ 29X 2,174,520 10/ l 939 Kuniansky 75/48X Primary ExaminerCharles W. Lanham Assistant ExaminerR. Spencer Amear Attorney-Waters, Roditi, Schwartz & Nissen ABSTRACT: A gas cupola furnace for making metals, said furnace having a hearth comprising various chemical reagents which contact the molten metals for the purpose of changing the chemical composition thereof.

GAS CUPOLA FURNACE W ITH A SPECIAL SUPERHEAT HEARTH The present invention relates to the field of metallu gy. and more particularly to methods for making metal and gas cupola furnaces for effecting these methods.

Known in the prior art is a gas cupola furnace as disclosed in the Soviet Authors Certificate No. 167613, Class 31a; 1/01. The medium part of the shaft of this cupola furnace is provided with two shoulders: the lower one for maintaining the column of charge materials and the upper one for preventing the charge from falling into the lower part of the cupola furnace shaft, viz, the superheating chamber.

The melting and superheating of metal are effected in the cupola furnace due to the combustion of a gaseous fuel in its lower part. This cupola furnace is suitable for making liquid metal heated to a temperature sufficient for casting thinr walled parts. The productive capacity of the gas cupola furnace is higher than that of a coke cupola furnace of the same size, it being of a more simple design and occupying a smaller floor space.

In the process of melting metal in this cupola furnace, however, it is impossible to control the chemical composition of the metal obtained, to effect deoxidation thereof and to introduce useful constituents into or remove harmful impurities from the metal being superheated. All these operations are effected outside the cupola furnace, which involves the use of an additional equipment and cooling of metal.

An object of the present invention is tov eliminate the abovesaid disadvantages. Other objects and advantages of the invention will become more fully apparent from a consideration of the following description thereof.

The principal object of the invention is to provide a method of making metal in a gas cupola furnace, providing for controlling the chemical composition of metal superheated in the cupola furnace by introducing useful constituents and removing harmful impurities therefrom.

This object is achieved due to the provision of a method of making metal in a gas cupola furnace, comprising, according to the present invention, superheating of the molten metal in the basin of the hearth, containing reagents passing into the metal and changing its chemical composition.

This object is accomplished in a gas cupola furnace, whose hearth, according to the invention, contains carbonaceous materials. The hearth of the gas cupola furnace may also comprise substances containing silicon.

The hearth of the cupola furnace may contain reagents, contributing to the removal of sulfur from limestone, for example, lumps of fired limestone. i

The nature of the present invention will become more fully apparent from a consideration of the following description of an exemplary embodiment of the method of making metal and of an embodiment of the cupola furnace for carrying same into effect, taken in conjunction with the accompanying drawing, representing a vertical section of the gas cupola furnace of the invention.

The shaft of the cupola fumace has two shoulders laid therein, namely, the lower shoulder l for maintaining the column of charge materials and the upper shoulder 2 for preventing the charge from getting'into the lower part of the cupola furnace. Hence, the shaft of the cupola furnace is divided into two zones. The upper zone accommodates the charge and affords the space for melting same, while the lower zone, called superheating chamber, is designed for superheating liquid metal. Both shoulders are provided with channels 3 and 4 for effecting water cooling. The lower part of the superheating chamber is provided with a hearth 5 having a basin 6 for the metal to be superheated. The lining of the walls over the basin has a number of tunnels for the combustion of gaseous fuel in the cupola furnace. Depending upon the necessity of carrying out a corresponding manufacturing process, the hearth is made of a material containing the corresponding reagents passing over into the molten metal found in the basin. Thus, for carburizing the liquid iron, the bottom of the basin is made of graphite lumps, coke charcoal and other solid carbonaceous materials, the size and amount thereof being selected depending upon the required degree of the metal carburization.

To prevent the lumps of the carbonaceous material from floating up to the surface when the basin is filled with the liquid metal, the gaps between the lumps are stopped up with a composition containing powdered graphite during the making of the hearth, said composition also containing crushed ferrosilicium (or ferromanganese) and other active constituents. as well as binding materials.

With a view to reducing the content of sulfur in iron, materials are introduced into the hearth contributing to the transfer of sulfur into slag, for instance, lumps of fired limestone. To increase the content of chromium in the metal, the hearth is made of chromium-magnesite materials. The presence in the hearth of 75 percent ferrosilicium or silicocalcium improves the quality of metal, this being conducive to partial deoxidation and modification of iron, as well as to some increase in the silicon content.

The cupola furnace of the invention operates in the following manner. Prior to starting the melt, the gas cupola furnace is heated up to the temperature in the superheating chamber of the order of l600 C. Then the charge, consisting of metal and fluxes, is charged into the cupola furnace shaft. The hot gases, while passing between the shoulders provided in the shaft, melt down the metal which flows into the basin falling dropwise from the shoulder. Thebasin on the bottom of the superheating chamber is filled with metal, from whose surface the slag continuously flows into the forehearth. The surface of metal is thus permanently kept clean from the slag which contributes to the superheating of metal. Falling, as it were in a rain, drops'produce on the metal surface in the basin some kind of boiling effect, which contributes to a better superheating of the metal.

The superheated metal is made to wash the bottom, whence reagents are passing over thereinto, after which the metal is tapped into the forehearth for molten metal. l r

Testing of the method of making metal in the gas cupola furnace has demonstrated that it is both possible and simple to saturate iron with carbon, silicon, manganese, chromium and other constituents, as well as it is practicable to carry into effect the desulfun'zing and deoxidizing of metal and to influence the run of other metallurgical processes.

Though the present invention is described in connection with its preferred embodiment, it is evident that there may be allowed modifications and variants that do not depart from the scope and idea of theinvention.

We claim:

' 1. In a gas cupola furnace for making metal having a melting zone and a superheat zone, said superheat zone comprising a hearth for receiving molten metal from said melting zone and means for superheating metal in the hearth, said hearth being made of carbonaceous materials for carburizing the superheated metal therein.

2. A gas cupola furnace as claimed in claim 1 wherein said hearth is hollowed out to form a basin for the molten metal therein.

3. A gas cupola furnace as claimed in claim 1 wherein said carbonaceous materials are constituted as lumps with gaps therebetween, and means between the lumps and filling said gaps.

4. In a gas cupola furnace for making metal said superheat zone comprising, a hearth having a melting zone and a superheat zone made of materials contributing to the removal of sulfur from metal and means for superheating the metal insaid hearth.

5. A gas cupola furnace according to claim 4, wherein the material contributing to the removal of sulfur is fired limestone.

6. A gas cupola furnace as claimed in claim 1 comprising means for melting said metal and dispersing the same dropwise onto said hearth which forms a basin to collect the metal.

modating a charge, the shoulders being offset vertically and horizontally with the lower of the shoulders retaining the charge in the upper zone and the upper part of the shoulders preventing the charge from falling into the lower zone. 

2. A gas cupola furnace as claimed in claim 1 wherein said hearth is hollowed out to form a basin for the molten metal therein.
 3. A gas cupola furnace as claimed in claim 1 wherein said carbonaceous materials are constituted as lumps with gaps therebetween, and means between the lumps and filling said gaps.
 4. In a gas cupola furnace for making metal said superheat zone comprising, a hearth having a melting zone and a superheat zone made of materials contributing to the removal of sulfur from metal and means for superheating the metal in said hearth.
 5. A gas cupola furnace according to claim 4, wherein the material contributing to the removal of sulfur is fired limestone.
 6. A gas cupola furnace as claimed in claim 1 comprising means for melting said metal and dispersing the same dropwise onto said hearth which forms a basin to collect the metal.
 7. A gas cupola furnace as claimed in claim 6, comprising means for continuously draining slag from the metal in said basin.
 8. A gas cupola furnace as claimed in claim 7 comprising a shaft over said basin and including two shoulders dividing the shaft into upper and lower zones, the upper zone accommodating a charge, the shoulders being offset vertically and horizontally with the lower of the shoulders retaining the charge in the upper zone and the upper part of the shoulders preventing the charge from falling into the lower zone. 